Systems and methods for people counting using beam-forming passive infrared sensors having a dynamically configurable field of view

ABSTRACT

A detection system ( 10 ) and a detection method ( 2000 ) are disclosed herein. The system includes a PIR sensor ( 12 ) positioned in an area comprising a plurality of sub-areas, the motion sensor comprising an optical device ( 22 ) having a plurality of sub-lenses ( 26, 28, 30 ), each sub-lens of the plurality of sub-lenses having a field of view (FOV) corresponding to a sub-area of the plurality of sub-areas. The system further includes at least one processor ( 32 ) coupled to the PIR sensor and configured to: activate the plurality of sub-lenses to generate a total sensor FOV comprising each FOV of the plurality of sub-lenses; and dynamically control the plurality of sub-lenses to subdivide the total sensor FOV, wherein the subdivided sensor FOV is smaller than the total sensor FOV.

FIELD OF THE DISCLOSURE

The present disclosure is directed generally to systems and methodsusing beam-forming passive infrared sensors for determining how manyoccupants are in a location and/or localizing the positions of theoccupants in the location.

BACKGROUND

Automating building functions (e.g., heating, ventilation, and airconditioning, or HVAC systems, lighting systems, etc.) can be used toboth optimize occupant comfort and minimize energy usage, and thereforecost, of maintaining a building. For example, passive infrared (PIR)sensors are a cost-efficient solution ubiquitous in building lightingcontrol systems to control when lighting fixtures are turned on whenareas are occupied. PIR sensors sense motion by detecting a differentialin IR radiation between at least two sensing elements. A lens, typicallya Fresnel lens, is used to focus IR radiation on the sensing elementsand determines the field of view (FOV) of the sensor. To minimize costsfor an installation, the FOV is usually set as wide as possible (e.g.,90 degrees or greater) for the detection area to be as large aspossible. By detecting motion in combination with hold times aftermotion detection, a packaged PIR sensor for lighting control attempts todiscriminate between presence and vacancy states for an area within theFOV of the sensor. However, such motion detection is not granular thus,while motion can be detected it cannot be determined how many people arecausing the motion or where the people are located.

Typically, altering the FOV of a PIR sensor can be done mechanically,but such alterations cannot be made easily since they require manualintervention. Others have attempted to use PIR sensors for detecting,locating, and tracking an individual using movement analysis. However,such efforts require as many pyroelectric components as optical beams,image analysis, or using multiple PIR sensors focused on the same area,where the FOV is modulated and coded using physical masks.Unfortunately, increasing the number of pyroelectric components andusing image analysis is cost prohibitive. Additionally, using multiplePIR sensors to cover a single area compromises the accuracy of detectingpresence/vacancy and motion events due to double counting when a singleperson or motion is detected by multiple sensors. The presence/vacancydetection of conventional PIR sensors for lighting control may also notbe accurate when using a single PIR sensor to cover an area which leadsto false-on or false-off triggers.

Accordingly, there is a need in the art for systems and methods usingbeam-forming passive infrared sensors to enable the accuratedetermination of a number of occupants in a location and/or localizationof the positions of the occupants in the location.

SUMMARY OF THE INVENTION

The present disclosure is directed to inventive systems and methodsusing beam-forming passive infrared sensors to determine how manyoccupants are in a location and/or localize the positions of theoccupants in the location, which can be particularly useful foroperating a control system in the location or for providing data forother applications. In particular, embodiments of the present disclosureare directed to improved systems and methods for dynamically focusingthe FOV of a PIR sensor on different positions within an area enablingtargeted presence/vacancy determination and people counting. Theimproved systems and methods described herein do not require multiplesensors focused on a single area or a separate physical mask that can beprogrammed to change the direction of detection. Various embodiments andimplementations herein are directed to a beam-forming PIR sensor thatuses a Fresnel lens with an electrochromic photothermal material toenable dynamic configuration of the sensor FOV without using a separatephysical device.

Generally, in one aspect, a detection method is provided. The detectionmethod includes the step of providing a first motion sensor in an areahaving a plurality of sub-areas, wherein the first motion sensorincludes an optical element having a plurality of sub-lenses, eachsub-lens of the plurality of sub-lenses having a field of view (FOV)corresponding to a sub-area of the plurality of sub-areas. The detectionmethod further includes the steps of activating the plurality ofsub-lenses to generate a total sensor FOV including each FOV of thesub-lenses, receiving at the plurality of sub-lenses, infrared energyemitted by an individual or an object present in the area, focusing bythe plurality of sub-lenses, the received infrared energy onto at leasttwo sensing elements including a pyroelectric element, and dynamicallycontrolling the plurality of sub-lenses to subdivide the total sensorFOV, wherein the subdivided sensor FOV is smaller than the total sensorFOV.

In embodiments, the step of controlling the plurality of sub-lensesfurther includes activating or deactivating at least one sub-lens togenerate the subdivided sensor FOV.

In embodiments, at least one sub-lens of the plurality of sub-lensesincludes an electrochromic photothermal material.

In embodiments, the subdivided sensor FOV is smaller than 90 degrees orsmaller than 45 degrees.

In embodiments, the method further includes the steps of providing asecond motion sensor in the area, wherein the second motion sensor isadjacent to the first motion sensor, obtaining positions of the firstand second motion sensors in the area during a commissioning process,and determining a relative coverage of the first and second motionsensors.

In embodiments, the method further includes the step of controlling thepluralities of sub-lenses in the first and second motion sensors suchthat a least one sub-lens from each of the first and second motionsensors is configured to be activated to form a combined detection area.

In embodiments, the method further includes the steps of determining anoverlapped area between the first and second motion sensors andcontrolling the pluralities of sub-lenses in the first and second motionsensors such that a least one sub-lens from each of the first and secondmotion sensors is configured to be activated to form a combineddetection area.

In embodiments, the method further includes the steps of generatingsensor information indicating motion or presence in the subdividedsensor FOV and controlling a lighting system based on the generatedsensor information.

In embodiments, the method further includes the step of controlling theplurality of sub-lenses to further subdivide the subdivided sensor FOV,wherein the additionally subdivided sensor FOV comprises a different setof activated sub-lenses. In embodiments, the method further includes thestep of generating sensor information indicating motion or presence inthe subdivided sensor FOV and/or the additionally subdivided sensor FOVand time multiplexing the generated sensor information to facilitatecontrol of a lighting system based on the generated sensor information.

Generally, in another aspect, a detection system is provided. Thedetection system includes a first motion sensor positioned in an areacomprising a plurality of sub-areas, the first motion sensor includingan optical device having a plurality of sub-lenses, each sub-lens of theplurality of sub-lenses having a field of view (FOV) corresponding to asub-area of the plurality of sub-areas, wherein the plurality ofsub-lenses are configured to receive infrared energy emitted by anindividual or an object present in the area and focus the receivedinfrared energy onto at least two sensing elements configured togenerate a differential signal. The detection system further includes atleast one processor coupled to the first motion sensor and configured toactivate the plurality of sub-lenses to generate a total sensor FOVcomprising each FOV of the plurality of sub-lenses and dynamicallycontrol the plurality of sub-lenses to subdivide the total sensor FOV,wherein the subdivided sensor FOV is smaller than the total sensor FOV.

In embodiments, the at least one processor of the detection system isconfigured to activate or deactivate at least one sub-lens to generatethe subdivided total sensor FOV.

In embodiments, at least one sub-lens of the plurality of sub-lensesincludes an electrochromic photothermal material.

In embodiments, the detection system further includes a second motionsensor arranged in the area adjacent to the first motion sensor andwherein at least one sub-lens from each of the first and second motionsensors is configured to be activated to form a combined detection areaincluding at least portions of sub-areas within the total sensor FOVs ofthe first and second motion sensors.

In various implementations, the inventive systems and methods involvemotion sensing devices configured as sensor nodes in a wireless sensingnetwork. The sensing devices may operate in a communication network,such as a conventional wireless network, and/or a sensor-specificnetwork through which sensors may communicate with one another and/orwith dedicated other devices. In some configurations, one or moresensors may provide information to one or more other sensors, to acentral controller or server, or to any other device capable ofcommunicating on a network with one or more sensors. A centralcontroller may be located locally with respect to the sensors with whichis communicates and from which it obtains sensor data. Alternatively oradditionally, a central controller maybe remote from the sensors, suchas where the central controller is implemented as a cloud-based systemthat communicates with multiple sensors which may be located at multiplelocations and may be local or remote with respect to one another.

The processor described herein may take any suitable form, such as, oneor more processors or microcontrollers, circuitry, one or morecontrollers, a field programmable gate array (FGPA), or anapplication-specific integrated circuit (ASIC) configured to executesoftware instructions. Memory associated with the processor may take anysuitable form or forms, including a volatile memory, such asrandom-access memory (RAM), static random-access memory (SRAM), ordynamic random-access memory (DRAM), or non-volatile memory such as readonly memory (ROM), flash memory, a hard disk drive (HDD), a solid-statedrive (SSD), or other non-transitory machine-readable storage media. Theterm “non-transitory” means excluding transitory signals but does notfurther limit the forms of possible storage. In some implementations,the storage media may be encoded with one or more programs that, whenexecuted on one or more processors and/or controllers, perform at leastsome of the functions discussed herein. It will be apparent that, inembodiments where the processor implements one or more of the functionsdescribed herein in hardware, the software described as corresponding tosuch functionality in other embodiments may be omitted. Various storagemedia may be fixed within a processor or may be transportable, such thatthe one or more programs stored thereon can be loaded into the processorso as to implement various aspects as discussed herein. Data andsoftware, such as the algorithms or software necessary to analyze thedata collected by the tags and sensors, an operating system, firmware,or other application, may be installed in the memory.

It should be appreciated that all combinations of the foregoing conceptsand additional concepts discussed in greater detail below (provided suchconcepts are not mutually inconsistent) are contemplated as being partof the inventive subject matter disclosed herein. In particular, allcombinations of claimed subject matter appearing at the end of thisdisclosure are contemplated as being part of the inventive subjectmatter disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. Also, the drawings are notnecessarily to scale, emphasis instead generally being placed uponillustrating the principles of the present disclosure.

FIG. 1A is a schematic depiction of a side view of a typical passiveinfrared (PIR) sensor;

FIG. 1B is a schematic depiction of a top view of the PIR sensor shownin FIG. 1A;

FIG. 2 is an example detection system including a PIR sensor accordingto aspects of the present disclosure;

FIG. 3A is a Fresnel lens and its corresponding FOV according to aspectsof the present disclosure;

FIG. 3B is an example lens facet focusing infrared radiation ontosensing elements according to aspects of the present disclosure;

FIG. 4 shows a plurality of activatable sub-lenses of a motion sensorconfigured to achieve a wide FOV according to aspects of the presentdisclosure;

FIG. 5 shows a plurality of activatable sub-lenses of a motion sensorconfigured to achieve a medium FOV according to aspects of the presentdisclosure;

FIGS. 6 and 7 show an activatable sub-lens of a motion sensor configuredto achieve a narrow FOV according to aspects of the present disclosure;

FIG. 8 shows a plurality of activatable sub-lenses of a motion sensorconfigured to achieve a subdivided FOV according to aspects of thepresent disclosure;

FIG. 9 shows a plurality of activatable sub-lenses of a motion sensorconfigured to achieve another subdivided FOV according to aspects of thepresent disclosure;

FIG. 10 shows example resulting detection areas for the wide FOV of FIG.4 according to aspects of the present disclosure;

FIG. 11 shows example resulting detection areas for the medium FOV ofFIG. 5 according to aspects of the present disclosure;

FIG. 12 shows example resulting detection areas for the narrow FOV ofFIG. 6 according to aspects of the present disclosure;

FIG. 13 shows example resulting detection areas for the subdivided FOVof FIG. 8 according to aspects of the present disclosure;

FIG. 14 shows example resulting detection areas for the subdivided FOVof FIG. 9 according to aspects of the present disclosure;

FIG. 15 shows a single activated sub-lens of an example motion sensorconfigured to achieve a subdivided FOV according to aspects of thepresent disclosure;

FIG. 16 shows two activated sub-lenses of an example motion sensorconfigured to achieve another subdivided FOV according to aspects of thepresent disclosure;

FIG. 17 shows a detection zone formed from active beams generated fromthe motion sensor of FIG. 15 and the motion sensor of FIG. 16 accordingto aspects of the present disclosure;

FIG. 18 shows the single activated sub-lens of the example motion sensorof FIG. 15 ;

FIG. 19 shows another single activated sub-lens of an example motionsensor configured to achieve another subdivided FOV according to aspectsof the present disclosure;

FIG. 20 shows a detection zone formed from active beams generated fromthe motion sensors of FIGS. 18 and 19 according to aspects of thepresent disclosure;

FIG. 21 shows an example of collaborative beamforming according toaspects of the present disclosure; and

FIG. 22 describes an example detection method according to aspects ofthe present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

The present disclosure describes various embodiments of systems andmethods for using beam-forming passive infrared sensors to determine howmany occupants are in a location and/or localize the positions of theoccupants in the location, which can be particularly useful foroperating a control system in the location or for providing data forother applications. Applicant has recognized and appreciated that itwould be beneficial to use a PIR sensor to provide presence detectionwith finer spatial granularity. Accordingly, Applicant has providedimproved systems and methods using a single PIR sensor by itself orwithin a network to provide dynamically configurable FOVs to facilitatepeople counting and/or localization. Exemplary goals of utilization ofcertain embodiments of the present disclosure are to provide differentstatic FOVs enabled through remote control, for example, to fine tunesensor FOVs for commissioning purposes or in response to changing officelayouts, eliminating the need to manually reconfigure or move orreinstall sensors. Additional goals of utilization of certainembodiments of the present disclosure are to provide motion counts, orpresence in various sub-areas to increase the spatial granularity ofsensor information, via a single sensor, to count people more accuratelyor enable finer zonal control of a lighting system. Further goals ofutilization of certain embodiments of the present disclosure are toprovide the exact positions of people or objects with collaborativebeamforming which can help improve the accuracy and reduce the problemof overlapping between the sensors in a network.

Referring to FIGS. 1A and 1B, schematic depictions of side and top viewsof a passive infrared (PIR) sensor 1 are depicted, respectively. The PIRsensor 1 includes a lens 2 that encompasses two or more pyroelectriccells or elements that are connected in a differential way such thatthey remove the direct component of a heat signal and generate an outputsignal (e.g., a differential signal) that represents the difference ofthe output of all of the cell elements. The lens 2 is typically aFresnel lens configured to increase a FOV of the sensor by focusing IRradiation on the sensing elements. A typical total sensor FOV is 90degrees as shown in FIG. 1A using reference number 4. A total sensor FOVcan also be larger. As such, the sensor 1 is configured to detect alarge FOV in order to detect presence via motions in this singular largeFOV. The FOV can be dynamically adjusted as described herein withoutmechanically or optically occluding the sensing elements.

FIG. 2 shows an example detection system 10 including a PIR sensor inaccordance with aspects of the present disclosure. The system 10includes a sensor 12 having a sensing unit 20 which includes the two ormore pyroelectric cells or elements referenced above. In exampleembodiments, the sensing unit includes four sensor elements (e.g., twopositive and two negative). In other example embodiments, the sensingunit can include a single element. In front of the sensing unit 20,there is an optical element 22 which includes one or more activatablelenses. While the sensor in FIG. 2 includes the optical element 22within a lens structure, other embodiments could include the opticalelement 22 as part of the lens structure or attached to the inside oroutside surfaces of the lens structure. For example, the optical element22 can be a Fresnel lens arranged to direct radiation or light from amultitude of angles onto the sensing unit 20. Although FIG. 2 shows anaperture angle of less than 90 degrees, it practice, the FOV may belarger than 90 degrees or 180 degrees or larger. The sensing unit 20 andthe optical element 22 define a maximum sensor coverage area or a totalsensor FOV, which is the area around the sensor 10 that is “visible” tothe sensing unit 20 through the optical element 22. Although FIG. 2shows the optical element 22 in a flat configuration, it should beappreciated that optical element 22 can be arranged in any suitableconfiguration, for example, a quadrilateral shape (e.g., a rectangle) ora dome shape mirroring the shape of the sensor.

FIG. 2 shows a side view of the optical element 22 including a pluralityof sub-lenses 26, 28, and 30 which are configured to be activated ordeactivated to subdivide the total sensor FOV. The sub-lenses of theoptical element 22 are made of an electrochromic photothermal materialwhere the individual sub-lenses can be turned on or off via anelectrical control signal. The electrochromic material may be a glass ora coating that is both electrochromic (e.g., optical propertiesactivated by an electrical signal) and photothermal (e.g., capable ofblocking or attenuating IR radiation).

In embodiments, the detection system 10 includes at least one processor32 for controlling the activation and deactivation of the sub-lenses 26,28, and 30. The at least one processor 32 can include a processing unitand a memory or a microprocessor. Additionally, the system 10 includeswireless communication means 34 in the form of a wireless communicationinterface. In embodiments, the wireless communication interface isadapted to operate according to the ZigBee standard. However, anysuitable interface is contemplated. The at least one processor 32controls the wireless communication means 34.

In the embodiment shown in FIG. 2 , sub-lens 30 is arranged in a centerof the optical element 22, sub-lenses 26 are arranged around sub-lens30, and sub-lenses 28 are arranged around sub-lenses 26 yet any suitableconfiguration is contemplated. For example, the sub-lenses can bearranged in an oval shape or any other suitable shape. When thesub-lenses are deactivated, they are in an opaque state blocking lightfrom reaching the sensing unit 20. When the sub-lenses are activated,they are in a transparent state allowing light to pass through to reachthe sensing unit 20. When all of the sub-lenses are activated andtherefore in a transparent state, the FOV of the sensing unit 20 isequivalent to the maximum sensor coverage area, or a total sensor FOV.When a portion of the sub-lenses is deactivated and therefore in anopaque state, the total sensor FOV is subdivided, narrowed, or targetedas further explained below.

Referring to FIG. 3A, a Fresnel lens and its corresponding FOV isdepicted. A top view of sensor 12 is shown on the top of FIG. 3Aincluding a Fresnel lens having a plurality of sub-lenses. Sub-lens A inFIG. 3A corresponds to sub-lens 30 discussed above with reference toFIG. 2 . Similarly, sub-lenses B, B′, E1, E1′, E2, E2′, D1, D1′, D2, andD2′ shown surrounding sub-lens A correspond to sub-lenses 26 discussedabove with reference to FIG. 2 . Sub-lenses C, C′, F1, F1′, F2 and F2′shown surrounding sub-lenses B, B′, E1, E1′, E2, E2′, D1, D1′, D2, andD2′ correspond to sub-lenses 28 discussed above with reference to FIG. 2. Each sub-lens is also known as a facet which can activated anddeactivated as described herein and each facet focuses a beam ofinfrared radiation onto two or more sensing elements. The correspondingFOV of the Fresnel lens is depicted on the bottom of FIG. 3A. As one canappreciate, each lens corresponds to a portion of the total sensorcoverage area. As shown in FIG. 3B, a single sub-lens (e.g., sub-lens Ain FIG. 3A) focuses infrared radiation onto at least two sensor elementsS1 and S2 which can be paired as a positive and a negative. Eachsub-lens when activated generates a detection area D of a single beam oftwo rectangles. Although the focused radiation may take the shape of anoval, for example, the detected radiation is only the radiation thatfalls onto the sensing elements (represented as rectangles). Therefore,the resulting detection area for a single sub-lens is two rectanglesthat represent the projected area of radiation that falls onto the twosensor elements.

It should be appreciated that any sub-lens by itself can be activated orany combination of sub-lenses can be activated in any configuration. Inexample embodiments, one or more sub-lenses can be activated in aregular geometry with respect to longitudinal and lateral axes of thesensor when viewed from the top. In other embodiments, one or moresub-lenses can be activated in an irregular geometry with respect tolongitudinal and lateral axes of the sensor when viewed from the top.The total sensor FOV of a sensor having the sub-lenses described hereincan have a subdivided, narrowed, or targeted FOV based on the shape ofthe sub-lenses, the number and configuration of the sub-lenses, and thenumber and placement of the sensing elements. In other words, the shapeof the lenses, the number and configuration of the lenses, and thenumber and placement of the sensing elements determine the FOV of thesensor.

FIGS. 4, 5, and 6 show, respectively, wide, medium, and narrow FOVsaccording to aspects of the present disclosure. In FIG. 4 , all of thesub-lenses are activated; thus, the FOV is equivalent to the maximumsensor coverage area or a maximum total sensor

FOV. In FIG. 5 , some of the sub-lenses are activated and some of thesub-lenses are deactivated; thus, the FOV is less than the maximumsensor coverage area or the maximum total sensor FOV in FIG. 4 .Specifically, in addition to sub-lens A, sub-lenses B, B′, D1, D1′, D2,D2′, E1, E1′, E2, and E2′ are also activated while the remainingsub-lenses in the outermost ring are not activated. In FIG. 6 , only asingle sub-lens is activated (e.g., sub-lens

A in FIG. 3A) while the remaining sub-lenses are deactivated; thus, theFOV is further decreased or subdivided, narrowed, or targeted. Thetargeted FOV shown in FIG. 6 is advantageous if a person or an object isdetected directly underneath the PIR sensor. The targeted FOV shown inFIG. 5 is broader than that shown in FIG. 6 but still more granular thanthat shown in FIG. 4 which has all of the sub-lenses activated.

FIGS. 7, 8, and 9 show, respectively, an inner circle FOV, a middle ringFOV, and an outer ring FOV according to aspects of the presentdisclosure. The FOV in FIG. 7 is identical to the FOV in FIG. 6 . FIG. 8includes additional activated sub-lenses B, B′, D1, D1′, D2, D2′, E1,E1′, E2, and E2′ when compared with the FOV in FIG. 7 , but the centralsub-lens A is deactivated in FIG. 8 . Thus, the FOV in FIG. 8 is broaderthan that shown in

FIGS. 6 and 7 , but still more granular than that shown in FIGS. 4 and 5. In FIG. 9 , the sub-lenses A, B, B′, D1, D1′, D2, D2′, E1, E1′, E2,and E2′ are all deactivated while sub-lenses C, C′, F1, F1′, F2, and F2′are activated.

FIG. 10 shows the resulting detection areas of each sub-lens activatedin FIG. 4 for a two element sensor. As one can appreciate in theembodiment of FIG. 10 , there is a single beam of a pair of rectangulardetection areas for each activated sub-lens. In other words, thedetection area for each facet is a beam projection of the radiation thatis focused and falls onto the two sensing elements. Movement within thedetection area of a facet that creates a differential signal across thetwo sensing elements of sufficient amplitude will result in a motiondetection. As shown in the embodiment of FIG. 10 , there are six pairsof detection areas corresponding to sub-lenses C, C′, F1, F1′, F2, andF2′, ten pairs of detection areas corresponding to sub-lenses B, B′, D1,D1′, D2, D2′, E1, E1′, E2, and E2′, and a single pair of detection areascorresponding to sub-lens A. When all of these sub-lenses are activated,the FOV is equivalent to the maximum sensor coverage area or a maximumtotal sensor FOV.

FIG. 11 shows the resulting detection areas of each sub-lens activatedin FIG. 5 . There are the ten pairs of detection areas corresponding tosub-lenses B, B′, D1, D1′, D2, D2′, E1, E1′, E2, and E2′, and a singlepair of detection areas corresponding to sub-lens A. The six pairs ofdetection areas corresponding to sub-lenses C, C′, F1, F1′, F2, and F2′are omitted in FIG. 11 . FIG. 12 shows the resulting detection areascorresponding to sub-lens A. The ten pairs of detection areascorresponding to sub-lenses B, B′, D1, D1′, D2, D2′, E1, E1′, E2, andE2′shown in FIGS. 10 and 11 are omitted in FIG. 12 . FIGS. 13 and 14show alternate resulting detection areas for the activated sub-lensesshown in FIGS. 8 and 9 , respectively.

As shown, any singular sub-lens or combination of sub-lenses can beactivated to enable motion detection in specific areas. For example, asingle activated sub-lens of an example motion sensor can be configuredto achieve a subdivided FOV as shown in FIG. 15 (e.g., sub-lens F2). InFIG. 16 , two activated sub-lenses of another example motion sensor canbe configured to achieve another subdivided FOV as shown (e.g.,sub-lenses F1 and F1′).

When two motion sensors are arranged such that the total sensor FOVs ofthe two motion sensors 101A and 101B at least partially overlap as shownin FIG. 17 , a targeted detection zone 102 can be formed by activatingthe sub-lenses shown in FIGS. 15 and 16 . In this way, sub-lenses frommultiple networked sensors can be activated to form a combined detectionarea using collaborative beamforming.

Alternatively or additionally, as shown in FIGS. 18, 19, and 20 ,sub-lenses from multiple networked sensors 102A and 102B can beactivated to form a combined detection area even when the FOVs of thesensors do not overlap. For example, a single activated sub-lens (e.g.,sub-lens F2) in sensor 102A and another single activated sub-lens (e.g.,sub-lens F1′) in sensor 102B can form a combined detection area usingcollaborative beamforming. Any number of activated sub-lenses can becombined to form detection areas using collaborative beamforming.

With different configurations of sub-lenses there can be many possibleoptions to sub-divide the sensor detection area. Subdividing the sensordetection area enables motion detection or occupancy sensing atdifferent spatial granularities. In other words, dynamically focusingthe FOV of a PIR sensor on different positions within an area enablestargeted presence/vacancy determination and people counting. The sensorinformation from the different positions, can reveal additionalinformation about how many occupants are in an area and/or where theyare located.

Embedded PIR sensors usually have overlap so they can provide seamlesscoverage to monitor the area. When the sensors are networked together asin a lighting internet of things (IoT) network, adjacent sensors can usecollaborative beamforming to scan across the area for presence detectionand people counting, reducing the inaccuracy due to overlap. FIG. 21shows an example of the collaborative beamforming. On the left side of

FIG. 21 , a distributed wireless sensor network (WSN) of PIR sensors orsensor nodes 200 is shown within an enclosed area that can be sensed bythe sensor nodes 200. Each sensor node 200 is configured to detect IRradiation in its total sensor FOV or within a targeted FOV as describedherein. In the distributed wireless sensor network, the sensor nodes 200are also configured to process the sensor information and transmit thesensor information directly to a manager node 202 or indirectly throughother sensor nodes. Once the data is obtained at the manager node 202,the data can then be transmitted to a back-end data center 204. On theright side of FIG. 21 , a hierarchical wireless sensor network of PIRsensors or sensor nodes 200 is shown within another enclosed area thatcan be sensed by the sensor nodes 200. Each sensor node 200 isconfigured to detect IR radiation in its total sensor FOV or within atargeted FOV as described herein and transmit such data to the clusterheads 206. The cluster heads 206 are configured to process the sensorinformation and transmit the data to the manager node 202. As in thedistributed network, the manager node 202 transmits the data to theback-end data center 204.

In an area having multiple PIR sensors, the sensor positions can beobtained during a commissioning process and then their relative coveragecan be determined. Once their relative coverage is determined, anyoverlapped areas between adjacent sensors can be determined as well.Through the coordination of a manager node 202 in a distributed WSNs ora cluster head 206 in a hierarchical network, the sensors 200 cancollaborate with each other to scan across the region to count thepeople in the area. An example of collaborative beamforming is shown inFIG. 21 where overlapped coverage is illustrated in the distributed WSNon the left.

An example detection method 2000 is described as follows with referenceto

In step 2001, a first motion sensor is provided in an area having aplurality of sub-areas. The first motion sensor includes an opticalelement having a plurality of sub-lenses, each sub-lens of the pluralityof sub-lenses has a field of view (FOV) corresponding to a sub-area ofthe plurality of sub-areas. In embodiments, the first motion sensor is aPIR sensor (e.g., sensor 12) and the optical element is a Fresnel lens(e.g., lens 12 and/or optical element 22). The plurality of sub-lensesare formed of an electrochromic photothermal material within or on thelens or optical element in embodiments. The sub-lenses can be embodiedas sub-lenses 26, 28, and 30 discussed above in reference to FIG. 2 orsub-lenses A, B, B′, C, C′, D1, D1′, D2, D2′, E1, E1′, E2, E2′, F1, F1′,F2 and F2′ discussed above in reference to FIG. 3A.

In step 2002, the plurality of sub-lenses are activated by at least oneprocessor (e.g., processor 34) to generate a total sensor FOV includingeach FOV of each of the sub-lenses. Using the electrochromicphotothermal material, when the sub-lenses are activated, they are in atransparent state allowing IR radiation to be passed through and focusedon the sensing units (e.g., sensing units 20) of the PIR sensor. Sinceall of the sub-lenses are activated, the total sensor FOV is equal tothe maximum possible sensor coverage area. In steps 2003 and 2004,respectively, infrared energy emitted by an individual or an object inthe coverage area is received at the plurality of sub-lenses and theinfrared energy is focused onto at least two sensing elements includinga pyroelectric element.

In step 2005, the at least one processor dynamically controls theplurality of sub-lenses to subdivide the total sensor FOV withoutmechanically or optically occluding the sensing elements. The subdividedsensor FOV is smaller than the total sensor FOV.

Based on the above, it should be appreciated that certain embodiments ofthe present disclosure provide different static FOVs enabled throughremote control, for example, to fine tune sensor FOVs for commissioningpurposes or in response to changing office layouts. This functionalityeliminates the need to manually reconfigure or move or reinstallsensors. Additionally, certain embodiments of the present disclosureprovide motion counts, or presence in various sub-areas to increase thespatial granularity of sensor information, via a single sensor, to countpeople more accurately or enable finer zonal control of a lightingsystem. Furthermore, certain embodiments of the present disclosureprovide the exact positions of people or objects with collaborativebeamforming which can help improve the accuracy and reduce the problemof overlapping between the sensors in a network.

It should also be understood that, unless clearly indicated to thecontrary, in any methods claimed herein that include more than one stepor act, the order of the steps or acts of the method is not necessarilylimited to the order in which the steps or acts of the method arerecited.

All definitions, as defined and used herein, should be understood tocontrol over dictionary definitions, definitions in documentsincorporated by reference, and/or ordinary meanings of the definedterms.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Multiple elements listed with“and/or” should be construed in the same fashion, i.e., “one or more” ofthe elements so conjoined. Other elements may optionally be presentother than the elements specifically identified by the “and/or” clause,whether related or unrelated to those elements specifically identified.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of” or, when used inthe claims, “consisting of,” will refer to the inclusion of exactly oneelement of a number or list of elements. In general, the term “or” asused herein shall only be interpreted as indicating exclusivealternatives (i.e. “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.”

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” “composed of,” and the like are tobe understood to be open-ended, i.e., to mean including but not limitedto. Only the transitional phrases “consisting of” and “consistingessentially of” shall be closed or semi-closed transitional phrases,respectively.

While several inventive embodiments have been described and illustratedherein, those of ordinary skill in the art will readily envision avariety of other means and/or structures for performing the functionand/or obtaining the results and/or one or more of the advantagesdescribed herein, and each of such variations and/or modifications isdeemed to be within the scope of the inventive embodiments describedherein. More generally, those skilled in the art will readily appreciatethat all parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the inventive teachingsis/are used. Those skilled in the art will recognize or be able toascertain using no more than routine experimentation, many equivalentsto the specific inventive embodiments described herein. It is,therefore, to be understood that the foregoing embodiments are presentedby way of example only and that, within the scope of the appended claimsand equivalents thereto, inventive embodiments may be practicedotherwise than as specifically described and claimed. Inventiveembodiments of the present disclosure are directed to each individualfeature, system, article, material, kit, and/or method described herein.In addition, any combination of two or more such features, systems,articles, materials, kits, and/or methods, if such features, systems,articles, materials, kits, and/or methods are not mutually inconsistent,is included within the inventive scope of the present disclosure.

1. A detection method, comprising the steps of: providing a first motionsensor in an area comprising a plurality of sub-areas, wherein the firstmotion sensor comprises an optical element having a plurality ofsub-lenses, each sub-lens of the plurality of sub-lenses having a fieldof view (FOV) corresponding to a sub-area of the plurality of sub-areas;activating the plurality of sub-lenses to generate a total sensor FOVcomprising each FOV of the sub-lenses; receiving at the plurality ofsub-lenses, infrared energy emitted by an individual or an objectpresent in the area; focusing, by the plurality of sub-lenses, thereceived infrared energy onto at least two sensing elements comprising apyroelectric element; and dynamically controlling the plurality ofsub-lenses to subdivide the total sensor FOV, wherein the subdividedsensor FOV is smaller than the total sensor FOV, and wherein at leastone sub-lens of the plurality of sub-lenses comprises an electrochromicphotothermal material.
 2. The method of claim 1, wherein the step ofcontrolling the plurality of sub-lenses further comprises activating ordeactivating at least one sub-lens to generate the subdivided sensorFOV.
 3. The method of claim 1, wherein the subdivided sensor FOV issmaller than 90 degrees.
 4. The method of claim 1, wherein thesubdivided sensor FOV is smaller than 45 degrees.
 5. The method of claim1, further comprising the steps of: providing a second motion sensor inthe area, wherein the second motion sensor is adjacent to the firstmotion sensor; obtaining positions of the first and second motionsensors in the area during a commissioning process; and determining acoverage of the first and second motion sensors.
 6. The method of claim5, further comprising the step of controlling the pluralities ofsub-lenses in the first and second motion sensors such that at least onesub-lens from each of the first and second motion sensors is configuredto be activated to form a combined detection area.
 7. The method ofclaim 5, further comprising the steps of determining an overlapped areabetween the first and second motion sensors and controlling thepluralities of sub-lenses in the first and second motion sensors suchthat at least one sub-lens from each of the first and second motionsensors is configured to be activated to form a combined detection area.8. The method of claim 1, further comprising the steps of generatingsensor information indicating motion or presence in the subdividedsensor FOV and controlling a lighting system based on the generatedsensor information.
 9. The method of claim 1, further comprising thestep of controlling the plurality of sub-lenses to further subdivide thesubdivided sensor FOV, wherein the additionally subdivided sensor FOVcomprises a different set of activated sub-lenses.
 10. The method ofclaim 9, further comprising the step of generating sensor informationindicating motion or presence in the subdivided sensor FOV and/or theadditionally subdivided sensor FOV and time multiplexing the generatedsensor information to facilitate control of a lighting system based onthe generated sensor information.
 11. A detection system, comprising: afirst motion sensor positioned in an area comprising a plurality ofsub-areas, the first motion sensor comprising an optical device having aplurality of sub-lenses, each sub-lens of the plurality of sub-lenseshaving a field of view (FOV) corresponding to a sub-area of theplurality of sub-areas, wherein the plurality of sub-lenses areconfigured to receive infrared energy emitted by an individual or anobject present in the area and focus the received infrared energy ontoat least two sensing elements configured to generate a differentialsignal; and at least one processor coupled to the first motion sensorand configured to: activate the plurality of sub-lenses to generate atotal sensor FOV comprising each FOV of the plurality of sub-lenses; anddynamically control the plurality of sub-lenses to subdivide the totalsensor FOV, wherein the subdivided sensor FOV is smaller than the totalsensor FOV, and wherein at least one sub-lens of the plurality ofsub-lenses comprises an electrochromic photothermal material.
 12. Thedetection system of claim 11, wherein the at least one processor isconfigured to activate or deactivate at least one sub-lens to generatethe subdivided total sensor FOV.
 13. The detection system of claim 11,further comprising a second motion sensor arranged in the area adjacentto the first motion sensor and wherein at least one sub-lens from eachof the first and second motion sensors is configured to be activated toform a combined detection area comprising at least portions of sub-areaswithin the total sensor FOVs of the first and second motion sensors.